1. Technical Field
The present invention relates to an electronic device, an electronic apparatus including the electronic device, and a moving object including the electronic device.
2. Related Art
In recent years, requirements of size reduction and high precision of an electronic apparatus require an electronic device including a quartz crystal resonator or any other resonation device to be increasingly small and highly precise. In particular, to be insensitive to ambient temperature to achieve high frequency stability, an OCXO (oven controlled xtal oscillator) or any other similar electronic device is used. An OCXO has a thermostatic oven in which a heat generator heats a crystal resonator and the space around the crystal resonator is maintained at a fixed temperature. A thus configured OCXO, however, includes not only the crystal resonator but also an IC, a chip inductor, and other parts for an oscillation circuit that have temperature-sensitive characteristics, and the frequency characteristic of the OCXO is undesirably not stabilized unless the temperatures of the parts described above are stabilized.
To address the problem described above, for example, JP-A-2010-98418 discloses a structure in which a heat generator is mounted on a resonator and an outer connection terminal of the resonator is connected to one surface of a substrate. Further, JP-A-2008-28620 discloses a configuration in which a heat generator is mounted on a resonator having a lead terminal and the lead terminal of the resonator or a terminal of the heat generator is connected to an edge of a substrate (side surface of substrate).
In the configuration in JP-A-2010-98418 described above, however, since the outer connection terminal of the resonator, on which the heat generator is mounted, is connected to one surface of the substrate, heat is conducted from the one surface of the substrate, which means that electronic parts disposed on the other surface of the substrate cannot be efficiently heated. Further, since the substrate itself can be heated only from the one side, the temperature of the substrate is not stabilized, and the temperatures of the electronic parts disposed on the substrate are not stabilized. In the configuration described in JP-A-2008-28620, since heat conducted from the resonator passes through the lead terminal having poor heat conductivity, the efficiency of heating the substrate decreases. Further, since the terminal of the heat generator is connected to a side surface of the substrate, the heat needs to be then conducted to the front and rear surfaces of the substrate, which means that heating efficiency is inferior to that in a case where the front or rear surface of the substrate is heated. As a result, the temperature of the substrate is not stabilized, and hence the temperatures of electronic parts disposed on the substrate are not stabilized.
As described above, in an electronic device having any of the configurations of the related art, it is difficult to efficiently conduct heat from a heated resonator to a substrate on which other electronic parts are mounted, undesirably resulting in a situation in which the temperature of each of the electronic parts disposed on the substrate and having a temperature-sensitive characteristic is not stabilized and hence the temperature-sensitive characteristic of the electronic device is not stabilized.